Oil refining process



OIL REFINING PROCESS Filed April l5, 1936 L ,ik

INVENTOR matically, ian `apparatus ,setup ,convenient for use.

Patented Dec. 21, 1937 UNITED STATES PATENT OFFICE OIL REFINING PROCESS Application April 15, 1936, Serial No. '74,402

8 Claims.

This invention is directed to the refining of petroleum distillate products containing mercaptans or other sulphur containing compounds which render them sour to the doctor test.

This invention has for its object the provision of a method of producing stable, sweetened petroleum distillates from such sour distillates by a method highly economical of reagents, capable of close control, and conveniently continuously operated, taking advantage of the catalytic effect of lead sulphide and related metallic sulphides. A further object is the accomplishment of such sweetening without the use of aqueous reagent solutions. A further object is the provision of convenient means for regeneration of the catalyst employed. Other objects andadvantages are in part obvious or may be pointed out hereinafter.v

This invention is based upon the discovery that such distillates may be sweetened by dissolving in them controlled amounts of oxygen and sulphur, and then .passing them into contact with a catalytic bed composed of finely divided lead sulphide supported` upon a carrier substance.

It is well known that leadsulphide in the form of "black strap, which is the precipitate formed when some gasolines are treated with aqueous sodium plumbite solution, is a moderately eiiective sweetening agent in the presence of caustic soda solution and that the activity of such solutions may be increased by blowing with air during the sweetening reaction or by intermittent withdrawal `from the sweetening operation and blowing with air to regenerate. It has also been proposed to form the lead sulphide by various means.

in and upon an inert lcarrier material of the nature of fullers earth, diatomaceous earth, asbesto's, ber,',an'd,the like, and topass the oil to be sweetened therethrough, intermittently regenerating the catalyst bed by watersolutions of sdiunisulphide." We have found that the eiectivenes of this process can ,be materially increased by rdissolving inthe oil`-pri`or,'tol'itsgcontact with the catalyticv bed, oxygen and sulphur.,

Inorder that our process maybe understood,A there" is attached;y v,to `and ,made apart of thisspeciiication aJdra-wing-showing diagram-` in ourprocess,` `In the single iigure .of this :drawing, sourcil :to` be sweetened is introduced throughy more readily pipe I and is pumped through pipe 2, injector 3, and pipe 4 into catalyst chamber 5, in the central portion of which between grids 6 and 1, there is maintained a body of catalyst 8, composed of lead sulphide precipitated in and on a proper 5 carrier material. Sweetened oil is removed from the system through pipe 9,. A controlled amountl of oxygen is dissolved in or admixed with the oil prior to its entry to the catalyst chamber. This oxygen is derived, in the present instance', from l0 gaseous oxygen stored under pressure in cylinder I0. Any suitable method may be used for the delivery of oxygen under controlled, reduced pressure in measured amounts into pipe II, the one herein shown consisting of the usual pressure rel5 ducing valve, gas meter, andpressure regulating valve commonly employed.l Pipe I I, protected by check valve I2, leads into the chamber of injector 3, and under the aspiration action of the jet of oil in the injector, the oxygen is intimately ad- 20 mixed with and dissolved in the oil. Sulphur is also introduced into the oil in controlled amounts prior to treatment, and this, is accomplished by using by-pass pipe I3, in which there is introduced a vessel I4 containing solid sulphur. v The25 oil owing through pipe I3 under the pressure differential established by injector 3-` is saturated with sulphur in vessel I4, and control of the valved line I3 establishes control of the amount of sulphur introduced into the treating system. 430` i and frequently give rise to obnoxious odors which 40.

. catalyst supported uponan inert carrier gave `rise f to vvery erratic results,v and 'only a small` amount of s weetening could be `performed beforeregen-fj, eration was required. The regeneration processes so far proposed require aqueous reagents, an'dlin.-r` traduce all. of the troubles inherentv in treating in an aqueous system. 50

We have found that the effectiveness of such a catalyst can be somewhat prolonged by admitting oxygen with the oil to be treated, and that it can be further prolonged to a very material degree by introducing sulphur with the oil to be treated in addition to the oxygen. We have further found that after the catalyst used in such an operation nally has been deprived of its effectiveness, it may be regenerated most conveniently by Washing with certain organic solvents.

For one catalyst we use lead sulphide precipitated in and on a carrier material, such as fullers earth, diatomaceous earth, pumice, activated alumina, or bone char, of which we prefer bone char and activated alumina. As an example of one method of prepaning this catalyst, bone char may be thoroughly wetted with a concentrated aqueous solution of lead acetate. The bone char may then be drained, partially dried, if desired, and exposed to hydrogen sulphide gas until conversion to lead sulphide is complete. Other reagents and method of securing such a catalyst Will be obvious to those skilled in the art.

To show the' effect of the additive reagents oxygen and sulphur, the following notes are given:

TABLE I Run No 1 2 3 4 Duration-hours 2. 25 2. 25 3 100 Rate of 110W GPM# catalyst 0. 0255 0. 0255 0. 0255 0. 0255 Oxygen cu. it./bbl 0. 0 0. 0 0. l2 0. 25 Sulphur #l bbl 0. 0 0. 088 0. 0 0. 041 Mercaptan sulphur content oi feed gm./ cc 0. 012 0. 012 0. 007 0. 007 Doctor on product Ofi Oi O. K O. K. Corro inn O. K.

(Catalyst bed-activated alumina plus lead sulphide containing about 6.5% lead sulphide by weight.) Note: Doctorof product Went slightly ol after 3 hours.

In the above tests the catalyst was the same in all cases, the rate of flow, and other reaction controlling conditions the same, and the gasoline sweetened was that currently produced by regularly established processing, runs 1 and 2 being made at one time, and runs 3 and 4 at a diierent time, the difference in mercaptan sulphur content being within the range of variation normally encountered. From the above, it will be observed that without added sulphur and oxygen, and with only sulphur added, no results were obtained. With only additive oxygen, eective life of the catalyst was short. With additive oxygen and sulphur, the eiective life, of the catalyst was prolonged at least more than 30 times. It may be observed that even* after the product becomes off to the doctor test, the treatment recommended will remove a very considerable percentage of the mercaptan sulphur. Additional dernonstration of the necessity of the presence of oxygen and sulphur may be observed by shutting off their supply to a regularly operating treatment, with following decrease in effectiveness of the treating step.

This method of treatment has also been found to be unusually eiective for kerosene sweetening. Kerosene sweetening in the ordinary manner frequently results in a serious loss in color of the sweetened product, which may be overcome only by expensive distillation or other'reprocessing. It has been found that by this method of treatment, kerosene may be completely sweetened with substantially no loss in color, as demonstrated by the followingdata:

TABLE E Sweetem'ng kerosene Duration-hours 106 Rate of flow GPM/ifi catalyst 0. 045 Oxygen cu. ft./bbl 0.19 Sulphur #/bbl 0.003 Mercaptan sulphur content of feed gm./100 cc less than 0.001

Doctor on product O. K. Drop in color of product 0 (Catalyst bed-bone char plus lead sulphide containing about 12.8% lead sulphide by Weight.)

It has been found that the catalyst, when exhausted may be revivied by washing with an organic solvent, such as benzol, or acetone, or a mixture of these, which apparently acts by the removal of a substance of a gummy or resinous character from the catalyst bed, which gummy material seems to be composed, at least in part, of sulphur compounds of high molecular weight, apparently acting as catalyst poisons, and which may be separated thereafter from the solvent by distillation, and the solvent recovered.

The amount of lead sulphide in the catalyst depends upon the nature of the catalyst, but in general, about 10% of the total Weight of catalyst may be lead sulphide. Other sulphides show very much less effect, lead being very markedly superior to sulphides of other metals. 'I'he effective life and activity of the catalyst depend somewhat upon the nature of the carrier, bone char apparently being best, activated alumina, pumice, and fullers earth beinguseful in the order indicated, with nonporous materials not useful, usually.

The amount of oxygen may be varied quite widely, say from 0.1 cubic foot per barrel, up to the limit of solubility under the condition of operation, although 0.3 cubic foot per barrel is usually sufficient for cracked gasolines derived from Mid- Continent crude, and less than 0.2 cubic foot per barrel for the usual corresponding kerosenes. Sulphur may be added in widely varying amounts, depending somewhat upon the sourness of the oil being treated, the preferred range being from 0.003# per barrel with usual Mid-Continent kerosenes, to about 0.03# per barrel for normally sour cracked gasolines of Mid-Continent origin, 0.05 being a usual upper limit, as determined by the minimum proportion necessary for the required break when the oil is tested with doctor solution.

The catalyst is not sensitive to the presence of Water in the usual amounts encountered in feed stocks of this nature. Neither is it unduly sensitive to hydrogen sulphide present in the feed stock, as are many sweetening processes.

Other metallic sulphides have been found to be active as catalytic materials in this process, such as, for example, the water insoluble sulphides generally, as characterized by the sulphides of mercury, lead, copper, manganese, nickel, and iron.

We claim:

1. A method of treating sour petroleum distillates Without the use of aqueous alkaline solutions comprising the following steps: admixing oil with a gas containing free oxygen and with elemental sulphur and passing it through a filter bed consisting of a metallic sulphide insoluble in water supported by a porous, inert carrier.

2. A method of treating sour petroleum distillates without the use of aqueous alkaline solutions comprising the tions comprising the following steps: admixing oil with a gas containing free oxygen and with elemental sulphur and passing it through a filter bed consisting of lead sulphide supported by a porous, inert carrier.

3. A methodof treating sour petroleum distillates without the use of aqueous alkaline solutions comprising the following steps: admixing the' oil with a gas containing free oxygen and with elemental sulphur, passing it through a filter bed consisting of lead sulphide supported by a porous, inert carrier, and intermittently revivifying the filter bed by washing it with an organic solvent having the power of removing gummy deposits therefrom. 4

4. A method of treating sour petroleum distillates Without the. use of aqueous alkaline solufollowing steps: admixing the oil with a gas containing free oxygen and with elemental sulphur, passing it through a filter.

bed consisting of lead sulphide supported by a porous, inert carrier, and intermittently revivifying the filter bed by washing it with an organic solvent selected from the group consisting of acetone, benzol, and mixtures of the two.

5. A method of treating sour gasoline without the useof aqueous alkaline solutions comprising the following steps: admixing with the gasoline not in excess of 0.5 cubic foot of oxygen per barrel and not in excess of 0.05 pound of elemental sulphur per barrel, and passing the mixture through a filter bed composed of a porous carrier material upon which has been deposited about 10% of its Weight of lead sulphide.

6. A method of sweetening sour kerosene without the use of aqueous alkaline solutions without substantial loss of color comprising the following steps: admixing with the kerosene not in excess of 0.5 cubic foot per barrel of oxygen and not in excess of 0.005 pound of elemental sulphur per barrel, and passing the mixture' 8. A method of treating sour petroleum distillates without `the use of aqueous alkaline solution comprising the following steps: adrnixing oil with a gas containing free oxygen and with elemental sulphur and passing it through ,a filter bed consisting of a metallic sulphide insoluble in water supported by bone char.

JOHN HAPPEL.

DONALD W. ROBERTSON. 

